Landskrona Citadel, 16th century fortress in Landskrona, Sweden.

Landskrona Citadel is a 16th-century fortress in the town of Landskrona in southern Sweden, built with four round corner towers around a central square courtyard and surrounded by a wide water-filled moat. The complex also includes earthwork ramparts and outbuildings that together form a complete defensive ensemble still standing today.

King Christian III of Denmark ordered the fortress built between 1549 and 1559 to control the Oresund strait, one of the most important sea routes in northern Europe at the time. After the Treaty of Roskilde in 1658, the region passed from Denmark to Sweden, and the citadel has been in Swedish hands ever since.

The citadel's north round tower served as a prison from the early 18th century, first for prisoners of war and from 1827 for those sentenced to life. It remained a prison until 1940, when neutral Sweden reactivated the fortress for military use after the German invasion of Denmark and Norway. The western tower's 16th-century dungeon was entered through a hatch, with a drop of four to five metres.

The outer grounds and courtyard are open during the day throughout the year, while access to the interior buildings is usually available through guided tours in the summer months. Comfortable footwear is a good idea, as the site covers a large area with uneven surfaces including cobblestones and grass paths.

North of the fort, between the second, third and fourth moats, lies Sweden's oldest allotment-garden area, whose garden houses are attractions in themselves. The site is also known as Rothoffs Museikoloni, the country's only allotment-garden museum, and it keeps the layout of the plots and cottages of that gardening movement.